Ventura County sheriff’s deputies are investigating the death of a county jail inmate, authorities announced Wednesday.

Authorities said that at 11:15 a.m. Tuesday, deputies noticed Jeffrey Louis Kibler, 53, of Ventura, was experiencing a medical issue while in custody.

Jail medical staff members were called to evaluate Kibler, who was described as coherent and able to communicate about his condition, authorities said. From the evaluation, jail medical personnel determined Kibler’s health was deteriorating and additional assistance was required.